1. Field of the Invention
The present invention relates to a fluid-sealed type vibration isolating apparatus having an electromagnetic oscillator, and more particularly to a fluid-sealed type vibration isolating apparatus in which a vibration isolating mechanism section which is to be connected to a vibrating body and has an insulator, a fluid chamber and so on, and a vibrating mechanism section having an electromagnetic oscillator and so on for propagating a pulsating air pressure composed of duty waves (pulse waves) to a balancing chamber constituting the vibration isolating mechanism section, are so provided as to be separated from each other.
2. Description of the Prior Art
Among vibration isolating apparatus, the ones used in engine mounts for automobile and the like must be able to deal with a wide range of frequencies, because engines which are power sources are used under various conditions from the idle running to the maximum rotational speed. Moreover, recently, tuning of engine mounts has been conducted for the purpose of cutting of muffled noise caused by the vibrations in a relatively high frequency band. In order to cope with these plural conditions, there already has been a fluid-sealed type vibration isolating apparatus with an oscillator invented. The apparatus comprises an internal fluid chamber and, further, an electromagnetic oscillator provided in this fluid chamber to vibrate at a specified frequency. For example, Japanese Patent Unexamined Publication No. 9-49541 discloses such a fluid-sealed type vibration isolating apparatus with an oscillator.
In the above-described conventional apparatus, a vibration isolating mechanism section comprising an insulator, a fluid chamber and so on is integrally formed with a vibrating mechanism section comprising a coil and so on, and the vibrating isolating apparatus constructed as described above is installed between an engine which is a vibrating body and a chassis frame member. In the apparatus having such construction, if it is intended to increase the force produced by the oscillator, there arises a problem that the vibration isolating apparatus has to be increased in size as a whole such as to increase the coil in diameter, length and so on. However, the vibration isolating apparatus of this type should be installed between the engine and the chassis frame member, so that the installation space is limited, resulting in the difficulty of increasing the size. Further, it is apprehended that the vibration isolating mechanism section suffers damage from the heat generated from the coil. In order to solve the above problems, it is therefore an object (subject) of the present invention to provide an electromagnetic vibration type fluid-sealed type vibration isolating apparatus in which a vibration isolating mechanism section and a vibrating mechanism section are separated from each other.